BEIJING -- On the eve of his departure for Asia last week, Defense Secretary William S. Cohen pressed the Clinton administration to let a U.S. arms maker sell spare parts to China, despite a ban on sales of military equipment imposed after the Tiananmen Square massacre in 1989, administration officials say.

Cohen did not advocate a general lifting of the sanctions, the officials said, but rather suggested making an exception in the case of Sikorsky Aircraft of Stratford, Conn., the maker of Black Hawk helicopters.

Sikorsky, which sold 24 unarmed Black Hawks to China's military in 1984, has been lobbying the administration to allow it to sell China replacement engines and other parts, arguing that these should no longer be considered military equipment prohibited by the Tiananmen sanctions.

In internal discussions leading up to Cohen's 3 1/2 -day visit to China, which began yesterday evening, the administration rejected the idea as premature, and Cohen agreed to support that decision, the officials said, speaking on condition of anonymity.

The officials said, though, that the administration was considering ways to improve relations with China, and that easing the sanctions was among them.

That raised the prospect that at least some of the sanctions could be lifted, possibly in time for President Clinton's visit to China later this year, although officials emphasized that no decisions had been reached. One official said a decision at this time to lift, even slightly, the sanctions on any equipment that would be used by the Chinese army would provoke too great an outcry on Capitol Hill and elsewhere, and overshadow whatever benefits the United States received in exchange.

"That's a whole lot of heat to take for some spare parts," the official said.

Cohen declined through his spokesman, Kenneth H. Bacon, to talk about his discussion of the sanctions, saying the administration's internal deliberations should remain private.

In an interview with reporters during his 12-day tour of Asia, Cohen said China had to do more to improve human rights, among other things, before the United States could lift any sanctions. But he also made it clear that the sanctions, now nearly a decade old, would not go on indefinitely.

Asked about the possibility of lifting them, he said, "Sometime in the future it may be possible, but I don't foresee it at this particular time."

Nonetheless, Cohen's willingness to consider an exception to the sanctions underscored the extent to which he is prepared to find ways to improve relations with China in general and its military in particular.

During his visit to China, which will include meetings with senior military leaders and President Jiang Zemin, Cohen hopes to take steps to increase contacts and build confidence between the U.S. and Chinese militaries.

Tomorrow, he and Chinese Defense Minister Chi Haotian are scheduled to sign the Military Maritime Consultation Agreement. The agreement -- a set of rules governing contacts between the countries' navies -- is meant to avoid unintended clashes on the open seas.

A major part of Cohen's visit will be devoted to finding ways to increase cooperation with China's military, which remains wary of the U.S. presence in the region, particularly U.S. support for Taiwan.

"I think we have to take our relationship step by step and not rush it," Cohen said in an interview yesterday.